To meet the demand for wireless data traffic having increased since deployment of 4G communication systems, efforts have been made to develop an improved 5G or a pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘Beyond 4G Network’ or a ‘Post LTE System’.
The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), reception-end interference cancellation and the like.
In the 5G system, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.
In an orthogonal frequency division multiplexing (OFDM) system, one of synchronization operating schemes may be a scheme of operating synchronization by generating a training symbol of a repeating pattern.
FIG. 1 illustrates an example of a synchronization operating scheme in an OFDM system. In the synchronization operating scheme of FIG. 1, a transmitter (or a transmitting side) may transmit at least one training symbol 110 between data symbols 120 and 130. One training symbol may include a sequence of one or more training signals. In other words, a training symbol may be expressed as a training signal sequence, and two or more arbitrary training signals (e.g., 100 and 102) included in each training symbol may have a correlation 104 with each other. That is, the at least one training symbol 110 may have the characteristic (e.g., a repeating pattern) that there are correlations 104, 106 and 108 between training signals.
A receiver (or a receiving side) may receive the training symbol 110, and synchronize by identifying the correlations 104, 106 and 108 between training signals constituting the training symbol 110. For example, the receiver may synchronize by using the correlation 104 between the training signal 100 and another training signal 102 included in the at least one training symbol 110 among the training symbols transmitted from the transmitter.
However, a system that cannot allocate separate time resources (e.g., time resources for the training symbol 110) for synchronization, or cannot generate the training symbol 110 of a repeating pattern (e.g., a repeating pattern in which training signals have a uniform magnitude such as the correlations 104, 106 and 108), may not employ the synchronization operating scheme of the OFDM system.
For example, the FBMC system is a scheme of overlap-transmitting (or transmitting in an overlapping manner) symbols that are generated by multiplying two or more signals by different filter coefficients through a filtering process. A FBMC system, however, may not employ the synchronization operating scheme of the OFDM system, since the FBMC system has difficulty in satisfying the above two conditions. The FBMC system may have the characteristics that the FBMC system is robust against the time delay through a filter, and may transmit a signal having a low magnitude of a sidelobe. The FBMC system has not attracted attention since the FBMC system is complex compared with the OFDM system.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.